Try adding the Spanish (Latinamerica) layout, the default variant is fine, then make it the active layout.
Pressing the ; key in a US layout should get the ñ character, but it doesn't work.
The issue can be seen by opening dconf-editor and checking the value of org.gnome.desktop.input-sources.sources. The list should contain ('xkb','latam') but instead it has ('ibus', 'latam').
The issue fixed by https://github.com/elementary/switchboard-plug-keyboard/pull/338 is present in a fresh install of elementary OS Hera.
Steps to Reproduce
The issue can be seen by opening dconf-editor and checking the value of
org.gnome.desktop.input-sources.sources
. The list should contain('xkb','latam')
but instead it has('ibus', 'latam')
.